Illuminating means for thermostats



Patented June 8, 1954 ILLUMINATING MEANS FOR -THERMOSTATS LeiRoy D.Kiley, Glen Arm, Md; assignor to Bendix Aviation Corporation, Baltimore,Md., a

corporation of -Delaware Application-August 1; 1949,'Se rial No. 107,951

3 Claims. 1.

This invention relates to improvements in thermostats and particularlyto a. novelmeans of illumination for a thermostat.

- Conventional thermostatsused in connection with domestic heatinginstallations are provided with some arrangement for setting thetemperature. to which the thermostat responds. However, to observe thesetting it isnecessary for one to be quite close to the-thermostat, asthe setting indicia; are normally not large enough to permit reading'ofsame by. one in a position remote to the thermostat. In a. great manyinstallations, the thermostat is installed in a room frequently occupiedand it would be quite convenient for occupants ofthe room to be able todetect the setting f the thermostat from any position in the-room,withouthaving to changetheir position.

Accordingly, it is an object of the present invention to provide novelmeans for indicating the setting position of a thermostat in such a waythat the setting is visible and determinable from a position remote fromthe thermostat.

"The above-stated object is carried out by means of adial knob mountedon the thermostat housingfor setting the position of the thermostat. Thedial knob is. provided with a light-transmitting area corresponding tothe normal setting of the thermostat and within the housinglis mounted alight source in, proximity tothe'lightr transmitting area whereby anilluminated area,

servesto indicate the setting of the'thermostat. The li'ght transmittingarea is normally positioned adjacent the 70-degree Fuscalemarkingon theknob so that any temperature setting of the knob below or above 70degrees F.- canbe readily perceived.

An additional feature of the invention provides for illumination of athermometer mounted on the thermostat housing, the illumination beingprovided from thesame source of light .used for illuminating the dialknob.

iThe invention will be more fully understood by reference tothe drawingsannexed hereto; when taken in conjunction \viththe detailed descriptionbelow.

- Inithe drawings, Fig. 1 is a front elevationrview of a thermostatconstructed in accordance, with the present invention; Fig. Zis a sideview ofrthe thermostat shown in Fig; l, the view being partly inelevation and partly in section; Fig. 3 is a top view of-the dial knobshown in Figs. 1 and 2.

' Referring to the-drawings, there is shown a thermostat -4 comprising ahousing 5 having adial knob 6 mounted on its upper end and a temperatureresponsive unit mounted on its lower end.

The thermostat 4 can be of conventionaldesign embodying a suitabletemperature responsive element of the expanding fluid type adaptedto-actuate an electric switch by means-of a suitablemechanical linkage.lhe details of the temperature responsive element, switch, and linkageform nopart of the present invention and are not shown on the drawingsfor reasons of simplicity and brevity. Suffice to say that the'dial-knob6' is rigidly secured to a member t-by-meansof screw 9, the member 8'being connected to -the aforesaid mechanical linkage system in such amanner as to permit the electricswitch to be actuated through a selectedrange of temperatures. The member 831s adapted for rotation so thatrotation of the dial-knobt will serve to vary thesettingoi'thethermostat through aselected range of temperatures. -Thesetting of the thermostat ,is determined by the position ofthe knob 6with respect tothe fixed reference point -I0-on the housing 5.

The dial-knob t isshown as being of a subprovidedwith suitablescaleindicia, as indicated at I 4 in Fig. 1'. One methodof providing thescale indicia I4, in--the-ca-se of a knob constructedof a' transparent;plastic material, wouldbe to coat theinner surface with a substantiallyopaquecoating-material afterhavingmasked the outer surface I2corresponding to temperature scale markings and graduations.Similarly,-the-inner surface I I could be masked to correspond to-thearrow-shaped area I5. Another method of providing the indicia I4 wouldbe'to punch out sameon-a flexible strip andthen insert the'strip withinthe knob 6 by bending said-strip around the inner surface-I I; anannular recess I5 being'provided' to retain the strip-in'place. Whatevertechnique is, used; the end resultcomprisesa knob 6-presenting asubstantially. opaque surface except for' the scale; indicia I4; and.arrowshaped. area .I 5,

the-indicia and areapbeing capable-of transmit:

ting-light from Within theknob :6.

.MountedLWith-i. suitablynconnected. c an external source of 'elec,triceenergy. 'rn'lhe bulb 1.1.6:; is mountedrin :close proximity to thehollow interior of knob 6 Whereby a substantial portion of its light canbe transhe:. :housing .:5 .is alight .bulbcl 6 3 mitted from within theknob 6 through the indicia hi and area [5 to the outside. It is to benoted that the bulb i6 is mounted in the upper end of housing 5 at apoint relatively remote from the temperature responsive unit 7. Such aconstruction serves to eliminate any errors resulting from the effectson temperature responsive unit '1 of the heat generated by bulb it.

The housing 5 has an opening 11 in its front face. Mounted within thehousing 5 so as to cover the opening I! is a member H? to which isaffixed a thermometer IS. The member 18 is made of a suitablelight-transmitting plastic material and has an end 2! extending to apoint in close proximity to bulb IS. The member I8 is provided withsuitable temperature scale indicia 22 to cooperate with thermometer 19to give a visual indication of temperature. The member I8 is so formedand positioned as to have rays of light enter the end 2| and pass downthrough the memher Is in a manner well known in the art. If the indicia22 are formed by engraving or recessing same on the inner surface 23 ofmember 13, in a manner Well known in the art, the light transmittedthrough member l8 will be reflected outwardly by the indicia 22, therebycausing the indicia to stand out in substantially bold relief on themember 18.

With the arrangement described above, it is clear that the arrow-shapedarea IS, the indicia l4, and the indicia 22 will be illuminated and willserve to indicate the setting of the thermostat and the ambienttemperature. By locating the arrow-shaped area [5 in proximity to theTO-deeree F. marking on knob 6, any one can determine the setting of thethermostat by merely glancing at area 15. If this area is properlydimensioned, it is rendered visible from any point within a normal-sizedroom. In view of the fact that most domestic heating units are set tomaintain 70 degrees F. room temperature, the area has been convenientlypositioned in proximity to the 70 degree F. scale marking on knob 6.However, the area 15 could be positioned to correspond to some othertemperature, as 68 degrees F., '72 degrees F., etc. If the knob 6 isturned to the right or left, away from its normal position, the positionof the area 15, with respect to the fixed point 10 on housin 5, willreadily indicate whether the thermostat is set above or below the normalsetting position, and this can be determined by merely glancing at thethermostat from any position within the line of sight of the observer.Obviously, various color combinations can be worked out by proper choiceof materials or coating compositions to make the area I5 readilystand-out for ease of observation of its position. Further, the area l5and the indicia i4 and 22 could be formed by punching out the knob 6 andthe member 18 so as to allow the transmission of light therethrough.Also various combinations of colors and the proper choice of materialscan be utilized to make the indicia I4 and 22 readily stand-out for easeof observation.

What is claimed and desired to be secured by United States LettersPatent is:

1. An illuminated thermostat, comprising: a housing, a dial knob mountedon said housing and movable with respect to a relatively fixed point onthe housin for setting said thermostat, said dial knob carrying indiciarepresenting a temperature scale which cooperates with said 4 fixedpoint to indicate the actual setting of the thermostat and said dialknob also having delineated thereon a pointer or analogous configurationwhich is located adjacent a preselected temperature indicating characterand which also cooperates with said fixed point to give a visualindication of what the setting should be to obtain a given normaltemperature condition, said temperature scale and said pointer and atleast that portion of the knob in the immediate region of the scale andpointer having contrasting lighttransmitting properties to enhance thevisibility of the scale and pointer at a distance remote from thethermostat, said housing havin an opening in one side thereof, a memberformed of light-transmittin material mounted on said housing inproximity to said opening, a thermometer mounted on said member, and alight source common to said dial knob and said member located withinsaid housing immediately beneath said dial knob.

2. The combination defined in claim 1 wherein a temperature sensingelement is mounted on said housing at the bottom thereof so as to beremote from said light source.

3. An illuminated thermostat, comprising: a housing, a hollow dial knobmounted on said housing and rotatable with respect to a relatively fixedpoint on the housing for setting said thermostat, said dial knob carryinindicia representing a temperature scale which cooperates with saidfixed point to indicate the actual setting of the thermostat and saiddial knob also havin delineated thereon a pointer or analogousconfiguration which is located adjacent a preselected temperatureindicatin character and Which also cooperates With said fixed point togive a visual indication of what the setting should be to obtain a givennormal temperature condition, said temperature scale and said pointerand at least that portion of the knob in the immediate region of thescale and pointer being formed of material having contrastinglight-transmitting properties to enhance the visibility of the scale andpointer at a distance remote from the thermostat, said housing havin anopening in one side thereof, a member formed of light-transmittingmaterial mounted on said housin in proximity to said opening and havintemperature scale indicia thereon, a thermometer mounted on said member,and alight source common to said dial knob and said member locatedwithin said housing in the proximity of said dial knob.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,645,211 Zeal Oct. 11, 1927 2,097,625 Langlotz Nov. 2, 19372,200,801 Money May 14, 1940 2,254,134 Berry Aug. 26, 1941 2,309,060Glaser Jan. 19, 1943 2,328,485 Ott Aug. 31, 1943 2,333,492 Ridge Nov. 2,1943 2,472,638 White June '7, 1949 2,548,760 Allgeyer Apr. 10, 19512,566,026 Hughes, Jr Aug. 28, 1951 FOREIGN PATENTS Number Country Date845,909 France May 22, 1939 584,163 Great Britain Jan. 8, 1947

